US3856865A - Tetrabromo ether diol flame-retardant - Google Patents

Abstract

This invention is directed to the new compound, 2,3dihydroxyprop-1-yl 2,3,7,8-tetrabromooct-1-yl ether, and to flame-retarded polymeric compositions having said compound incorporated therein. The tetrabromooctyl ether diol is employed with particular advantage in the formation of flame-retarded cellular polyurethanes including self-extinguishing flexible foams.

Description

[Unite Papa et al.

[ TETRABROMO ETHER DIOL FL AMlE-RETARDANT [75] Inventors: Anthony Joseph Papa, Saint Albans,

W. Va.; William Robert Proops, Claymont, Del; Theodore Curtis Shields, Charleston, W. Va.

[73] Assignee: Union Carbide Corporation, New

York, NY.

[22] Filed: July 23, 1973 [21] Appl. No.: 381,747

Related US. Application Data [62] Division of Ser. No. 172,301, Aug. 16, 1971, Pat. No.

[52] US. Cl 260/615 R [51] llnt. Cl. C070 43/112 [58] Field of Search 260/615 R [111 msasns [451 Dec. M, 1974 [56] References Cited UNITED STATES PATENTS 3,009,888 ll/l96l Mueller-Tamm ct ill. zoo/2.5 FP 3,252,922 5/1966 Degener et al. 260/25 AS 3,465,031 9/1969 Stephenson 26()/2.5 Fl X Primary Examiner-Howard T. Mars Attorney, Agent, or FirmMarylin Klosty [57] ABSTRACT 1 Claim, No Drawings TETRABROMO ETHER DTOL FLAME-RETARDANT This is a division of application Ser. No. 172,301, filed Aug. 16, 1971, now U.S. Pat. No. 3,773,696.

The present invention relates to a particular tetrabrominated aliphatic polyol, its use as a flameretardant, and to polymer compositions, including polyurethanes, having said compound incorporated therein.

It is known that polyurethane polymers are manufactured by the reaction of polyfunctional isocyanates and polyfunctional active hydrogen-containing compounds such as in particular polyethers and polyesters containing free hydroxyl groups, and that cellular products are provided by effecting the reaction in the presence of a blowing agent. Notwithstanding their many useful properties which have contributed to their acceptance for many end-use applications in the transportation, building, household and textile industries, it is recog nized that an objectionable characteristic of polyurethanes, particularly when in cellular form, is their risk of flammability in applications where exposure to high temperatures and/or an open flame may be encountered. This problem which also exists with respect to other synthetic organic polymers such as, for example, thermosetting polyesters, polyepoxides and polystyrene, has of course received considerable attention with the result that a variety of compounds which are largely phosphorus-containing compounds and halogen-substituted compounds, are reported in the literature as effective agents for reducing flammability.

An important criterion in determining the efficacy of any particular flame-retarding agent is its ability to improve flame resistance with minimum impairment of desirable physical and mechanical properties of the polymer. As between various types of polymers including resinous coating compositions and cellular materials ranging from the open cell flexible foams to the closed and more highly cross-linked rigid foams, the flexible cellular polymers are inherently more difficult to flameproof without substantially upsetting the delicate balance of foam properties and open cell nature. For example, in British Pat. No, 1,063,605, it is re ported that polyurethane coating compositions of improved fire-retardant properties-are provided by the incorporation therein of 3-bromo-2,2- bis(bromomethyl)propanol, 2,2-bis(bromomethyl)- 1,3-propanediol, or a mixture thereof. The brominated diol which is also referred to in the art as dibromoneopentyl glycol, has the structural formula,

and does not, therefore, offer the processing advantagesof normally liquid flame-retarding agents.

A further factor which magnifies the difficulty ofproviding satisfactory flame-retarded flexible foams is that such foams generally exhibit .a greater tendency to ignite at temperatures lower than the combustion temperatures of rigid foams. Thus, a particular compound which may be effective in reducing the flammability of rigid foams, may be too stable at lower temperatures to be an efficient flame-retardant of flexible cellular materials.

A further problem especially associated with the formation of flame-retarded polyurethanes generally, is the tendency of many flame-retardants to cause foam scorching. This undesirable result is most commonly associated with halogen-substituted organic flameretardants and is often attributed to the release of hydrogen halide. Thus, although stability toward elimination of hydrogen halide appears necessary to minimize scorch, too high a degree of thermal stability will lower flame-retarding effectiveness.

Among other brominated aliphatic hydroxylsubstituted compounds reported in the literature as flameretarding agents for polyurethanes is 2,3- dibromopropanol which, in accordance with British Pat. Nos. 895,966 and 889,720, respectively, is used either as such or in combination with antimony oxide. Although this compound which has the formula. BrCH CHBrCH OH, is capable of providing selfextinguishing flexible polyurethane foams, it is found that the products are discolored due to scorching. This latter result is not surprising inview of the recognized relatively high reactivity of bromine bonded to the carbon atom beta to oxygen of the dibromoallyloxy grouping, CHBrCHBrCH O. The dibromoallyloxy group is also present as the sole dibrominated site of the ether alcohols of U.S. Pat. No. 3,252,922,

such as 2,3-dibromobutanediol-l ,4-mono-2- hydroxyethyl ether which has the formula, HOCH CHBrCHBrCH OCH Cl-l OH. Although the latter patent indicates that such compounds provide difficultly combustible elastic foams, as previously noted the ability to impart flame-retardant properties is only one of a number of criteria to be considered in determining the overall effectiveness of any particular flame-retarding agent.

It is desirable, therefore, and is a primary object of this invention to provide a novel bromine-substituted aliphatic polyol which finds particular application in the formation of flame-retarded, substantially scorchfree, cellular polyurethanes of good overall physical and mechanical properties and which offers the further advantage of being a normally liquid material compatible with various components employed in the production of polyurethanes.

Various other objects and advantages of the present invention will become apparent to those skilled in the art from the accompanying description and disclosure.

The present invention provides the particular tetrabrominated aliphatic ether diol, 2,3-dihydroxypropl-yl 2,3,7,8-tetrabromooct-l-yl ether, which is a new compound and has the formula:

BrCH CHBr(CH CHBrCHBrCH OCH CHOHCH OH This compound, which for convenience is also referred to herein as Compound I, is prepared by the bromination of 2,3-dihydroxyprop-l-yl 2,7-octadien-lyl ether. The present invention also provides flame-retarded polymer compositions such as in particular urethane polymers and other polymers that are normally susceptible to burning, having Compound I incorporated therein. In accordance with one aspect of this embodiment of the present invention, flame-retarded polyurethanes are provided by reacting a reaction mixture containing: (I) an organic polyisocyanate, (2) an organic compound containing an average of at least two active hydrogen atoms capable of reacting with isocyanato groups such as, in particular, polyether polyols and polyester polyols, and (3) the aforesaid dihydroxypropyl tetrabromooctyl ether of the present invention. The polyurethane-forming reaction is usually effected in the presence of a catalyst comprising an amine as an additional component of the reaction mixture. The flameretarded polyurethanes of the present invention may be produced as flexible, semi-flexible and rigid foams (i.e., cellular polyurethanes), flexible and stiff fibers, coatings, films, elastomers and the like. In producing flame-retarded cellular polyurethanes, the aforesaid reactionof (I), (2) and (3) is carried out in the presence of a blowing or foaming agent as an additional component of the reaction mixture.

The novel tetrabromooctyl ether diol of this invention possesses a particularly desirable combination of properties as a flame-retardant of cellular polyurethanes, especially flexible foams. For example, in addition to being a normally liquid material, it is compatible with components normally present in polyurethaneforming reaction mixtures such as, for example, polyether polyols. It is, therefore, readily amenable to use in the widely employed one-shot or single stage technique for producing flexible polyurethane foams. It is also found that the flame-retarding agent of this invention allows for the formation of flexible polyurethane foams which are self-extinguishing, substantially scorch-free and of overall good quality. A particularly noteworthy property of Compound I is that it imparts flame-retardant including self-extinguishing characteristics to flexible polyurethane foams without causing any substantial impairment of the desirably low compression set of flexible foams.

The novel flame-retardant of this invention is prepared as the bromination reaction product of 2,3-dihydroxyprop-l-yl 2,7-octadien-l-yl ether, as shown by the following equation (I):

COMPOUND I n This addition reaction is usually carried out at relatively low temperatures such as from about minus C. to about plus 10C. and proceeds rapidly at substantially atmospheric pressure. The reaction is preferably conducted in the substantial absence of light using about two mols of bromine per mol of the octadienyl ether diol reactant. The bromination reaction may be carried out in the presence or absence of a diluent or solvent. When used, suitable diluents include the halogen-substituted lower alkanes such as carbon tetrachloride, chloroform and methylene chloride, although other diluents which are liquid and substantially non reactive under the aforesaid conditions may be employed, such as trichloromonofluoromethane, 1,1,2- trichloro-l,2,2-trifluoroethane, benzene and the like. After the reaction, which may be carried out batchwise or in a continuous manner, the product is recovered by conventional techniques such as extraction or as the product remaining after removal of more volatile components. When the product of the reaction of equation '(I) has an acid number greater than about 1.0 mg.

KOH/gram and is to be used as the flame-retardant component of polyurethane-forming reaction mixtures containing an amine catalyst, it is preferred practice to subject the product to further purification to reduce the acid number to less than about 1.0, and most preferably to less than about 0.50 mg. KOH/gram. This is readily accomplished by treating the product with any relatively weak alkaline material such as sodium bicarbonate.

In addition to polyurethanes, Compound I can also be used to impart flame-retardancy to other solid synthetic organic polymers which are normally susceptible to burning. Among such additional polymers are: condensation polymers such as thermosetting polyesters, polyepoxides, and thermoplastic polyesters; and addition polymers derived from ethylenically unsaturated monomers such as ethylene, propylene, styrene, alkylsubstituted styrenes, lower alkyl acrylates and methacrylates, vinyl acetate, and other resinous polymers well known to the art.

The amount of Compound I which is incorporated into any particular polymer composition depends on several factors including the degree of flameretardancy desired, whether an additional flameretardant is employed, the chemical composition of the polymeric material, the physical nature (i.e., cellular or non cellular), and, with respect to cellular polymers, the nature of the cellular structure (i.e., flexible, semiflexible or rigid). Generally, Compound I is employed in an amount sufficient to provide in the polymer product, bromine in an amount from about 0.5 to about 20 weight per cent. In providing flame-retarded cellular polyurethanes including flexible polyurethane foams, Compound I is used in an amount sufficient to incorporate in the polymer at least about I and usually no more than about 10 weight per cent bromine, based on the combined weight of the polyisocyanate, active hydrogen-containing reactant and Compound I. In producing self-extinguishing, flexible polyurethane foams it is usually preferred to employ Compound I in an amount sufficient to provide a bromine content of at least about 1.5, and most preferably at least about 2, weight per cent, expressed on the aforesaid basis.

The polyisocyanates used in the manufacture of polyurethanes are known to the art and any such reactants are suitably employed in producing the flame-retarded compositions of this invention. Among the suitable polyisocyanates are those represented by the general formula:

wherein i has an average value of at least two and Q is an aliphatic, cycloaliphatic or aromatic radical which can be an unsubstituted hydrocarbyl group or a hydrocarbyl group substituted for example, with halogen or alkoxy. For example, Q can be an alkylene, cycloalkylene, arylene, alkyl-substituted cycloalkylene, alkarylene or aralkylene radical including corresponding halogen-substituted radicals. Typical examples of suitable polyisocyanates for use in preparing the flameretarded polyurethanes of this invention are: 1,6- hexamethylene diisocyanate, 1,4-tetramethylene diisocyanate, 1-methyl-2,4-diisocyanatocyclohexane, bis(4- isocyanatophenyl)methane, phenylene diisocyanates such as 4-methoxy-l,3-phenylenediisocyanate, 4- chloro-l ,3-phenylenediisocyanate, 4-bromo-l ,3- phenylenediisocyanate, 5,6-dimethyl-l ,3- phenylenediisocyanate, 2,4- and 2,6-tolylene diisocyanates, crude tolylene diisocyanate, 6-isopropyl-l,3- phenylenediisocyanate, durylene diisocyanate and triphenylmethane-4,4,4"-triisocyanate. Other suitable polyisocyanate reactants are ethylphosphonic diisocyanate and phenylphosphonic diisocyanate. Also useful are the polyisocyanates of the aniline-formaldehyde polyaromatic type which are produced by phosgenation of the polyamine obtained by acid-catalyzed condensation of aniline with formaldehyde. Polyphenylmethylene polyisocyanates of this type are available commercially under such trade names as PAP], AFPI, Mondur MR, lsonate 390P, NCO- 120, NCO-l0 and NCO-20. These products are low viscosity (50-500 centipoises at C.) liquids having average isocyanato functionalities in the range of about 2.25 to about 3.2 or higher, depending upon the specific aniline-toformaldehyde molar ratio used in the polyamine preparation. Other useful polyisocyanatesare combinations of diisocyanates with polymeric isocyanates containing more than two isocyanate groups per molecule. Illustrative of such combinations are: a mixture of 2,4- tolylene diisocyanate,2,6-tolylene diisocyanate and the aforesaid polyphenylmethylene polyisocyanates; and a mixture of isomeric tolylene diisocyanates with polymeric tolylene diisocyanates obtained as residues from the manufacture of the diisocyantes.

The amount of polyisocyanate employed varies slightly depending upon the nature of the polyurethane being prepared. In general, the polyisocyanates are employed in amounts that provide from 80 to 150 per cent. preferably from 90 to 120 per cent of the stoichiometric amount of the isocyanato groups required to react with all of the hydroxyl groups present in the other reactants of the polyurethane producing reaction mixture, including the hydroxyl groups of the tetrabromooctyl ether diol of this invention, the additional polyol-reactants described below and any water which may be present as a source of blowing action.

In producing the flame-retarded urethane polymers of the present invention, one or more polyols in addition to the tetrabromooctyl ether diol of the present invention is employed in the reaction with the organic polyisocyanate. Such additional active hydrogencontaining compounds have an average of at least two hydroxyl groups per molecule and include compounds which consist of carbon, hydrogen and oxygen and compounds which also contain phosphorus and/or halogen. Suitable classes of such active hydrogen containing compounds are polyether polyols, polyester polyols; lactone, polyols and phosphorus-containing polyols.

Among the suitable polyether polyols that can be employed are the alkylene oxide adducts of water or any of the following polyhydroxyl-containing organic compounds: ethylene glycol; diethylene glycol; propylene glycol; dipropylene glycol; trimethylene glycol; butylene glycols; glycerol; 1,2,6-hexanetriol; 1,1 ,ltrimethyolethane; 1,1,l-trimethyolpropane; 3-(2- hydroxyethoxy)-l,2-propanediol; pentaerythritol; 1,2- cyclohexanediol; sorbitol; sucrose; lactose; glycosides such as alpha-methylglucoside and alpha-hydroxyalkyl glucoside, fructoside and the like; compounds in which hydroxyl groups are bonded to an aromatic nucleus such as resorcinol, pyrogallol, phloroglucinol, di-, tri-, and tetra-phenylol compounds such as bis-(phydroxyphenyl)-methane and 2,2-bis-(p-hydroxyphenyl)-propane, and many other such polyhydroxyl compounds known to the art. The alkylene oxides employed in producing polyether polyols, which are also known as poly(oxyalkylene) polyols, usually have from 2 to 4 carbon atoms and are preferably ethylene oxide, propylene oxide and any combination thereof. In the preparation of mixed poly(oxyethylene-oxypropylene) polyols, the ethylene and propylene oxides may be added to the hydroxyl-containing reactant either in admixture or sequentially.

Suitable polyester polyols for use in the manufacture of polyurethanes are the reaction products of: (1) one or more of the aforesaid polyether polyols or the polyhydroxyl-containing organic compounds which are reacted with alkylene oxide to produce such polyether polyols, and (2) a polyfunctional organic carboxylic acid including aliphatic and aromatic acids. Typical examples of suitable polycarboxylic acids that can be employed in producing polyester polyols are: succinic, adipic, sebacic, azelaic, glutaric, pimelic, malonic and suberic acids; and aromatic acids such as phthalic, terephthalic and isophthalic acids and the like.

Other suitable polyols for use in the manufacture of the flame-retarded polyurethanes of this invention are: lactone-based polyols prepared by reacting a lactone such as epsiloncaprolactone or a mixture of epsiloncaprolactone and an alkylene oxide with a polyfunctional initiator such as a polyhydric alcohol, an amine, or an aminoalcohol; and phosphorus-containing polyols such as the alkylene oxide adducts of phosphoric acid, polyphosphoric acids such as triand tetraphosphoric acids, organo substituted phosphoric acids such as benzenephosphoric acid and the like.

The particular polyol reactant or combination of polyols employed depends upon the end-use of the polyurethane product which in turn determines whether the product is to be provided as a flexible or rigid material. For this purpose, the polyol reactant is usually characterized by its hydroxyl number which is defined as the number of milligrams of potassium hydroxide required for the complete neutralization of the hydrolysis product of the fully acetylate derivative prepared from 1 gram of polyol or mixture of polyols. The hydroxyl number can also be defined by the equation:

on: 56.1 X 1,000 Xf/M. w.

wherein OH hydroxyl number of the polyol f= average functionality, that is, average number of hydroxyl groups per molecule of polyol M.W. average molecular weight of the polyol ln producing rigid polyurethanes, the polyol preferably possesses a hydroxyl number from about 200 to about 1,000. In producing semi-flexible materials, the hydroxyl number is usually from about I00 to about'250. Lower hydroxyl numbers from about 32 to about are usually appropriate for the polyols employed in producing flexible polyurethanes. These ranges of hydroxyl numbers are not intended to be restrictive but are merely presented as illustrative of the relatively large number of possible polyols and combinations thereof that can be employed.

The urethane-forming reaction is usually carried out in the presence of a minor amount of a catalyst comprising an amine. Suitable amine catalysts include one or more of the following: N-methylmorpholine; N- ethylmorpholine; N-octadecylmorpholine; triethylamine; tributylamine; trioctylamine; N,N,N'N'-tetramethylethylenediamine; N,N,N,N'-tetramethyl-1,3- butanediamine; triethanolamine; N,N- dimethylethanolamine; triisopropanolamine; N- methyldiethanolamine; ther; hexadecyldimethy(amine; N,N-dimethylbenzylamine; trimethylamine; triethylenediamine (i.e., l,4- diazabicyclo[2.2.21octane); the formate and other salts of triethylenediamine, oxyalkylene adducts of the amino groups of primary and secondary amines and other such amine catalysts which are well known in the art of polyurethane manufacture. The amine catalyst may be introduced to the polyurethane-producing reaction mixture as such or as a solution in suitable carrier solvents such as diethylene glycol; dipropylene glycol; and 2-methyl-2,4-pentanediol (hexylene glycol).

The amine catalyst is present in the final urethaneproducing reaction mixture in an amount of from about 0.05 to about 3 parts by weight of active catalyst (that is, the amine exclusive of other components present in solutions thereof) per 100 parts by weight of polyol reactant.

ln producing polyurethanes from polyether polyols it is often desirable to include as a further component of the reaction mixture a minor amount of certain metal catalysts. Such supplementary catalysts are well known to the urethane art. For example, useful metal catalysts include organotin compounds, particularly tin compounds of carboxylic acids such as stannous octoate, stannous oleate, stannous acetate, stannous laurate, dibutyltin dilaurate, and other such tin salts. Additional metal catalysts are organocompounds of other polyvalent metals such as zinc and nickel (e.g., nickel acetylacetonate), or other such metal catalysts which are well known in the art of flexible polyether urethane foam manufacture. The amount of each such metal catalyst which can be present in the polyurethane-producing reaction mixture is from about 0.05 to about 2 parts by weight per 100 parts by weight of the polyether polyol starting material.

When it is desired to provide cellular polyurethanes, the reaction mixture also includes a minor amount of a foaming or blowing agent such as water which, upon reaction with isocyanate generates carbon dioxide in situ, or through the use of blowing agents which are vaporized by the exotherm of the reaction, or by a combi' nation of the two methods. These various methods are known in-the art. Thus, in addition to or in place of water, other blowing agents which can be employed in the process of this invention include methylene chloride, liquefied gases which have boiling points below 80F. and above minus 60F., or other inert gases such as nitrogen, carbon dioxide added as such, methane, helium and argon. Suitable liquefied gases include aliphatic and cycloaliphatic fluorocarbons which vaporize at or below the temperature ofthe foaming mass. Such gases bis(2-dimethylaminoethyl)eare at least partially fluorinated and may also be otherwise halogenated. lllustrative of the fluorocarbon blowing agents are trichloromonofluoromethane, dichlorodifluoromethane, l,l-dichloro-l-fluoroethane, 1,1,1- trifluoro-2-fluoro-3,3-difluoro-4,4,4-trifluorobutane, hexafluorocyclobutene and octafluorocyclobutane. When producing flexible foams, the generally preferred method of foaming is the use of water or a combination of water plus a fluorocarbon blowing agent such as trichloromonofluoromethane. On the other hand, in producing rigid foams the blowing agent is usually one of the aforesaid halogenated compounds.

The amount of blowing agent employed in the foaming reaction will vary with factors such as the density that is desiredin the foamed product. Usually, however, from about 1 to about 30 parts by weight of the blowing agent per parts by weight of polyol is employed.

In producing flame-retarded cellular polyurethanes in accordance with the method of this invention, a minor amount of a foam stabilizer is also usually present as an additional component of the reaction mixture. When used, the foam stabilizer is usually a poly(siloxane-oxyalkylene) block copolymer and may be any of such copolymers described in the art. Generally, the block copolymers comprise: (l siloxy units having the formula, Z SiO, (2) polyether-substituted siloxy units having the. ner l u a, Z..Q(C".H2 1LO)-1LC'L'H2- ,,,Si(Z)O, and (3) siloxy units having the formula, Z Si- 0 where: Z in each instance is a monovalent hydrocarbon group having from 1 to 12 carbon atoms such as alkyl and aryl groups, in particular methyl; Z is either Z, Z-C(O) or hydrogen, wherein Z is as aforesaid; -C,,,H is a bivalent hydrocarbon radical, usually of 2 to 5 carbon atoms, that links the respective silicon atoms of the polyether-substituted siloxy units to the polyether block, ZO(C,,H ,,O),, in which n has a value of from 2 to 4 and the average value of x is such that the average molecular weight of the polyether block is from about 200 to about 6000. Illustrative block copolymers for use as foam stabilizers in the foaming reaction of this invention are, for example, the copolymers described in US. Pat. Nos. 2,834,748; 2,917,480; 3,505,377; 3,507,815; 3,563,924; and in the US. Pat. application Ser. No. 109,587, flled Jan. 25, 1971, now abandoned. Such copolymer compositions are incorporated herein by reference to the aforesaid patents and application. When used, the foam stabilizer is present in the polyurethane-forming reaction mixture in an amount within the range of from about 0.2 to about 5 parts by weight or more, per 100 parts by weight of the polyol reactant.

The flame-retarded urethane polymers of the invention can take the form of foamed products, elastomers, surface coatings, castings and the like, and may be formed in accordance with any of the processing techniques known to the polyurethane art such as the oneshot, quasi-prepolymer and prepolymer techniques. For example, in accordance with the one-shot process, foamed products are produced by carrying out the reaction of the polyisocyanate, polyol and Compound I simultaneously with the foaming operation. In preparing the foamed products in accordance with the quasiprepolymer technique, the polyisocyanate is first reacted with a portion of the polyol to give a product having a high percentage of free-NCO groups (e.g., from 20 to 50 per cent), and the product is subsequently foamed by reaction with additional polyol and foaming agent. In the prepolymer technique, the isocyanate is reacted with a slightly less than stoichiometric quantity of polyol to form a prepolymer having a low percentage (e.g., from l to 10 per cent) of free-NCO groups, followed by reaction of the prepolymer with a blowing agent such as water to form the cellular material. In these various multistage methods, Compound 1 may be incorporated at any stage but is usually used in combination with the polyol reactant. Elastomers and castings are formed by reaction of the aforesaid prepolymer with a crosslinking agent having reactive hydrogens such as a diamine as typically'exemplified by a bis- (aminochlorophenyl)methane. Curing of the prepolymer by atmospheric moisture provides surface coatings.

The flame-retarded polyurethanes produced in accordance with the present invention are used in the same areas as conventional polyurethanes and are especially useful where fire-resistance properties are required. Thus the polymers are useful as textile interliners, cushions, mattresses, paddings, packaging, gaskets, sealers, thermal insulators and the like.

The following examples are merely illustrative of the present invention and are not intended as a limitation upon the scope thereof.

The following Examples l and 11 illustrate the preparation of the flame-retardant of this invention by the bromination of 2,3'-dihydroxyprop-1-yl 2,7-octadienl-yl ether. Preparation of this latter starting material is typically illustrated as follows:

To a three pint Chemco glass pressure reactor, there were charged 300 grams of glycerol, 60 grams of butadiene, 300 grams of t-butanol, 1.8-grams of palladium acetylacetonate and 1.56 grams of triphenylphosphine. The mixture was heated to 80C. and held there for about 45 minutes to yield 654 grams of liquid product. This procedure was repeated twice to give a total of 1981 grams of reaction product. This material was diluted with 3-4 liters'of water and extracted several times with ethyl ether. Theorganic extracts were combined and the solvent removed under vacuum. The higher boiling material was passed through a Rodneyl-lunt molecular still at 210220C. and 0.5 mm. pressure. The overhead product was redistilled to yield 2,3-dihydroxyprop-1-yl 2,7octadien-1-yl ether having a boiling point of 142l43C. at a reduced pressure of 0.4 mm. The structure of the product was confirmed by infrared and nuclear magnetic resonance spectroscopy. Upon analysis, the product was found to contain (on a weight per cent basis): C, 65.76; H, 10.04 (calcd. for C H O z C, 65.97; H, 10.07).

EXAMPLE 1 Preparation of 2,3-Dihydroxypropyl 2,3,7,8-Tetrabromooctyl Ether To 108 grams (0.54 mol) of 2,3-dihydroxyprop-1-y1 2,7-octadien-l-yl ether in 100 ml. of carbon tetrachloride at C., there was added a solution of 172.5 grams (1.08 mol) of bromine in 100 ml. of carbon tetrachloride while maintaining the temperature at minus 4 to 0C. The reaction was protected from light by means of aluminum foil and was carried out under nitrogen as an inert atmosphere. When one-half of the bromine solution had been added, another 100 ml. of carbon tetrachloride was added to the reaction mixture to lower the viscosity. The addition took 4.5 hours. When the addition was complete, the reaction mixture was allowed to warm up to ambient temperature on standing overnight. The resultant two phase, light orange, liquid product mixture was then subjected to reduced pressure (6.0 mm) at 50C. for one hour to remove volatile components. No evidence of HBr by a moist litmus test was noted at this point. The product had the following properties:

Brookfield Viscosity (25C.). centipoises 126.000 Hydroxyl Number. mg. KOH/gram 185.15 Acid Number, mg. KOH/gram 16.45

The product was subjected to analysis and found to contain 58.71 weight per cent bromine. The calculated Br content on the basis of C H B O is 61.5 weight per cent. 7

To lower the acid content, the product was taken up in chloroform and the chloroform solution washed with three -ml. portions of saturated sodium bicarbonate solution, and then with four 100-ml. portions of distilled water. After drying over anhydrous magnesium sulfate, the chloroform was removed under reduced pressure (3 mm.) at 50C., thereby providing 2,3-dihydroxyprop-l-yl 2,3,7,8-tetrabromooct-l-yl ether as a yellow liquid having an acid number of 0.412 mg KOH/gram.

EXAMPLE 11 Preparation of 2,3-Dihydroxypropyl 2,3,7,8-Tetrabromooctyl Ether The reaction of this example was carried out under nitrogen in a 5-liter capacity, stirred reaction vessel which was shielded from light and cooled in a Dry Iceacetone bath. To 338 grams (1.69 mols) of 2,3-dihydroxyprop-l-yl 2,7-octadien-1-yl ether in 1,000 m1. of carbon tetrachloride at about minus 2C., there was added 538 grams (3.38 mols) of bromine diluted with 500 ml. of carbon tetrachloride. The reaction mixture was maintained at a temperature of 2C. to 6C. throughout the bromine addition which took about 4 hours. At the end of this period, the reaction mixture thickened and was diluted with an additional 1,000 ml. of carbon tetrachloride after which the mixture was stirred and allowed to warm to room temperature over night. The two-phase reaction mixture was washed with four 500-ml. portions of a saturated (about 10 weight per cent) sodium bicarbonate solution followed by washing with water. The washed mixture was dried over magnesium sulfate, filtered, and volatile components were removed therefrom at 50C. and 5 mm.-

pressure in a rotary evaporator. The viscous liquid product had the following characteristics:

Brookfield Viscosity (25C.). centipoises 51,000 Hydroxyl Number, mg. KOH/gram 189.8 Acid Number, mg. KOH/gram 0109 Br Analysis (weight per cent) 61.06

EXAMPLES Ill-Vlll In accordance with these examples, flame-retarded flexible polyurethane foams were prepared by reacting and foaming a reaction mixture containing a polyether polyol, a polyisocyanate, water as the source of blowing action, an amine catalyst, stannous octoate, a silicone surfactant as the foam stabilizer and, as the flameretardant, 2,3-dihydroxyprop-1-yl 2,3,7,8- tetrabromooctyl ether of the present invention prepared in accordance with Example I. Flexible polyether foams were also prepared in which either: (1) no flameretardant was added (designated Run No. K), or (2) the known compound, dibromoneopentyl glycol, discussed and designated hereinabove as Compound A, was incorporated (designated Run Nos. C-1 and C-2).

In each of Examples Ill-VIII and Runs K, C-1 and C-2, the foam formulation contained the components identified in the following Table 1 wherein the relative proportions are expressed on the standardized basis of 100 parts by weight of polyether polyol, although the foams were produced on five times the scale.

TABLE I FOAM FORMULATlON A Component Parts by Weight Polyether Polyol having a hydroxyl 100 number of 56 produced by reacting glycerol and propylene oxide Tolylene Diisocyanatc (lndex 105) varied to obtain Index 105 4 Water Bis-[2-(N,N-dimethylamino)cthyllether 0.1 employed as a 70 weight per cent solution in dipropylene glycol Stannous Octoatc Varied Silicone Surfactant 0.5 Flame-Retardant Varied ne s otug'si of (MeSiO) 5. SiMe (wherein Me represents a methyl group) employed as an approximately 55 weight per cent solution in a solvent medium containing about 90 and 3 For specific proportions employed, refer to Table II herein.

The respective foams of Examples lll-Vlll were prepared using the following procedure:

The diisocyanate, silicone surfactant, polyether polyol and 2,3-dihydroxypropyl tetrabromooctyl ether were each weighed into and added as separate streams to a zfi-gallon container fitted with a baffle. The resultant mixture was stirred for 60 seconds with a high speed stirrer at 2,700 rpm. After the mixture was allowed to stand for seconds, it was stirred for an additional 15 seconds. During the latter period but after 5 seconds had elapsed, the amine catalyst and water were added as a premixed solution and, after the remaining l0-second period of stirring, the stannous octoate was added from a syringe. When the 15 seconds of stirring was completed, the mixture was quickly poured into a mold (14 inches X 14 inches X 6 inches) whereupon the respective masses foamed. Both the cream time and rise time were recorded which terms denote the interval of time from the formation of the complete foam formulation to l) the appearance ofa creamy color in the formulation and (2) the attainment of the maximum height of the foam, respectively. The foams were allowed to stand at ambient conditions for 2 days before flammability, physical and mechanical properties were determined. The specific relative proportions of those components of Foam Formulation A which were varied and the foam properties are given in Table 11.

The above procedure was also followed in providing the control foam of Run No. K except, of course, that no flame-retardant was added.

In providing the foams of comparative Run Nos. C-1 and C-2, the above procedure was also followed except that, in view of its solid nature, Compound A (dibromoneopentyl glycol) was added as a preformed solution in the liquid polyether polyol. The latter solution was prepared by: (1) combining Compound A and polyol in an amount sufficient to provide an 18 weight per cent solution of Compound A in the polyether polyol; (2) heating the resulting suspension at about C. for 1.5 hours to completely solubilize Compound A; and (3) blending the resulting solution in a predetermined amount with additional polyol to provide the relative proportion of Compound A per parts by weight of polyol indicated in Table I1.

Flammability properties, determined before and after accelerated aging, were measured in accordance with standard test proecedure ASTM D 1692-67 T, except that five samples of each foam were tested. The results are given in Table 11 below wherein:

SE" indicates that on the basis of the results obtained'in the aforesaid flammability test, the foam is rated as self-extinguishing.

Burning Extent denotes the burned length of the foam speciment; the flammability of the foam is proportional to the burning extent as measured by the aforesaid test.

Extinguishing Time denotes the time taken to give the specified burning extent.

Dry Heat Aging indicates that the foam specimen was heated in an oven at 140C. for 22 hours, as specified in test method ASTMD 1564-64 T, Sections 3844.

Humid Aging" indicates that the foam specimen was subjected to heating at C. for 5 hours in a steam autoclave, as specified in test method ASTM D 1564-64 T, Section 5.1.2.

In addition to flammability properties, Table II also indicates various physical and mechanical properties of the foams produced in Examples Ill-V111 and Runs C-1 and C-2 which properties were measured by subjecting the foam samples to the following standardizedtest procedures. 7 7

Air Porosity, which is a comparative measurement of the degree of openness of the cells of flexible foams, was determeind in accordance with the following test procedure: The test specimen of foam (4 inches X 4 inches X 16 inches) is compressed between two pieces of flanged plastic tubing (2% inches ID.) of an air porosity assembly maintained under an air pressure of 14.7 pounds. Air is drawn through the thickness (V2 inch) of the foam specimen at a velocity controlled to maintain a differential pressure of 0.1 inch of water across the thickness dimension. The air flow necessary to develop the requisite pressure differential is recorded and the air flow per unit area of the foam specimen is reported as the air porosity of the foam.

Density was measured as described in Sections 68-73 of ASTM D 1564-64 T except that the'test specimens had nominal dimensions of 4 inches X 4 inches X 1 114 ity (as indicated by the low air porosity values) and a less desirable compression set than the selfextinguishing foams of the present invention.

EXAMPLES IX-XV 5 i h, In accordance with these examples, another series of Tensile Strength and Ultimate Elongation were meaflexible polyurethane foams were prepared containing sured in accordance with Sections 81-87 (Suffix T) f the tetrabromooctyl ether diol of the present invention ASTM D 1564-64 T, after exposure of the foam speciprepared as described in Example 11 above, in amounts mens to the above-described dry heat aging conditions, uffic ent t provide from 1 t0 4 weight per cent broand are reported as the median values of three test mine in the polymer. Flexible foams were also prepared specimens for each foam sample. in which either no flame-retardant was used (Run No. Tear Resistance was measured as described in Suffix K-2) or in which dibromoneopentyl glycol (Compound G of ASTM D 1564-64 T and is reported as the median A) was employed as the flame-retardant (comparative value of three test specimens for each foam sample. 15 Run Nos. C-3 and C-4). In each instance, Foam Formu- Compression Load Deflection (CLD) which measlation A of Table I above was used, the specific ures the load necessary to produce a 25 per cent comamounts of those components which were varied being pression over the entire top area of the foam specimen, given in the following Table 111, following the procewas determined in accordance with Suffix D of ASTM dure described above with reference to the foam prepa- D 1564-64 T, both before and after exposure of the rations of Table II. The flammability and various physifoam specimens to the above-described humid aging cal and mechanical properties of the foamed products test conditions. are as given in Table III which also includes the results Compression Set at 90% constant deflection was deof the following determinations. termlned in accordance with Sections 12-18 of ASTM Flammability by Oxygen Index, which indicates the 1564-64 T, the amount of COmPYeSSIOH 561 t) being quantity of oxygen necessary to just sustain combustion expressed as a per cent of the original specimen thlckfthe foam sample, was measured using the procedure ness and is reported as the median of three test speclstandardized as ASTM D 2863 and General Electrics mens for each foam sample. Oxygen Index Tester.

TABLE II Example No. (Run N0.) (K) (01) (C-2) 111 iv V VI v11 vl11 Foam Formulation 'A Stannous Octoate, pts. by wt. 0.275 0.20 0.15 0.20 0.20 0.20 0.20 0.20 0.20 Diisocyanate, pts. by Wt. 498 53.3 54.6 51.8 52.0 52.2 52.4 52.6 53.0 Flame-Retardant. pts. by wt. 2.3-Dihydroxypropyl 2.3.7.13- 6.5 7.2 7.8 8.5 9.2 10.6 tetrabromooctyl Ether Dibromoneopentyl Glycol 5.0 7.0 Weight Per Cent Br in Polymer(1) 0 1.93 2.64 2.53 2.78 3.00 3.25 3.50 3.98 Cream Time, seconds 7 7 7 7 7 7 7 7 7 Rise Time, seconds 78 85 97 99 105 109 116 119 140 Flammability By ASTM D-l692-67 -T Before Sample Conditioning 7 Rating B SE SE SE SE SE SE SE SE Burning Extent, inches 3.2 3.1 2.8 2.8 2.4 3.4 2.6 2.5 Extinguishing Time, seconds 41 41 36 37 43 36 33 Burning Rate, inches/minute 5.60 4.59 4.53 4.55 4.46 4.08 4.68 4.33 4.50 After Dry Heat Aging Rating SE SE SE SE SE SE SE SE Burning Extent, inches 3.0 2.6 3.4 2.8 1.9 2.7 2.7 1.8 Extinguishing Time, seconds 30 33 37 36 28 24 31 21 Burning Rate, inches/minute 5.93 4.82 5.47 4.66 3.91 6.79 5.11 5.11 After I-Iumid Aging Rating SE SE SE SE SE SE SE SE Burning Extent, inches 2.2 2.1 1.8 1.8 1.6 1.5 1.5 1.8 Extinguishing Time, seconds 26 27 23 22 21 20 21 22 Burning Rate, inches/minute 4.96 4.58 4.78 4.79 4.41 4.39 4.29 4.90 Foam Properties: Density. lbsft. 1.49 1.50 1.59 1.61 1.64 1.59 1.66 1.63 Air Porosity, it /min/ft. 32 90 59 51 90 87 92 Tensile Strength. psi 19.2 20.0 14.8 17.3 14.7 14.8 15.7 17.8 Elongation. Per Cent 184 212 153 168 163 152 149 156 Tear Resistance, lbs/in. 2.53 2.57 2.33 2.03 2.14 2.37 1.80 1.97 25% CLD, psi 7.50 6.96 6.75 6.90 6.68 6.73 5.75 6.80 90% Compression Set. Per Cent 8.8 9.0 5.0 5.3 4.9 5.6 6.7 6.2

(1) Total weight of polymer is taken us combined weight M polyether polyol. diisocyunuitund flame-retardant.

The results of Table 11 show that in each'of Examples 'IlI-Vlll, the tetrabromooctyl ether diol of the present invention provided self-extinguishing flexible foams which maintained their self-extinguishing characteristics after accelerated aging under very dry and humid conditions. Although the foams produced incomparative Runs C-1 and C-2 were also stable, selfextinguishing foams, they exhibited poorer breathabil- Indentation Load Deflection (lLD Values) to 25% and deflections were measured in accordance with ASTM D 1564-64 T, Sections 1925 (Method A), except that the dimensions of the foam specimens employed were 12 inches X 12 inches X 4 inches. The Return Value is the percentage ratio of the load required to support the return 25% indentation after one minute as compared to the load required to support the initial 25% indentation after one minute. The Load Ratio is the ratio of the 65% and 25% ILD values, respectively.

In the following Table III, 3" indicates that on the basis of the results obtained in the aforementioned flammability test ASTM D 1692-67 T, at least one of 5 the foam samples burned to such an extent that it did not qualify as a self-exinguishing material; therefore, the foam is given a burning (B) rating.

TABLE 111 Example No. (Run No.) (K-Z) (C-3) (C-4) IX X XI X11 X111 XIV XV Foam Formulation A Stannous Octoate, pts. by wt. 0.275 0.20 0.15 0.25 0.25 0.25 0.20 0.20 0.20 0.20 Diisoc anate,pts. by wt. 49.8 53.3 54.6 50.5 51.0 51.3 51.8 52. 52.6 53.3 Flameetardant. pt slTiy wt. 2.3-Dihydroxypropyl 2378- 2.5 3.8 5.1 6.4 7.8 9.2 10.7 tetrabromooctyl Ether Dibromoneopentyl Glycol 5.0 7.0 Weight Percent Br in Polymer 1.93 2.64 1.00 1.51 2.01 2.49 3.00 3.50 4.02 Cream Time, seconds 7 7 7 7 7 7 7 7 7 7 Rise Time, seconds 76 85 96 80 80 80 92 94 92 93 Flammability By Oxygen Index Test Oxygen Index 0 177 0.215 0.214 0.207 0.209 0.212 0.213 0.214 0.216 0.221 Flammability By ASTM D-169267 T Before Sample Conditioning Rating B SE SE B SE SE SE SE SE SE Burning Extent. inches 2.3 1.9 2.4 2.2 2.2 1.9 1.5 1.4 Extinguishing Time. seconds 29 26 38 26 27 24 20 19 Burning Rate, inches/minute 5.63 g 4.89 4.46 4.24 4.96 4.77 4.70 4.45 4.34 After Dry Heat Aging Rating Y SE SE B SE B SE SE B Burning Extent. inches 2.6 2.6 3.0 3.0 2.7 Extinguishing Time, seconds 32 33 34 31 Burning Rate, inches/minute 4.77 5.15 5.00 5.34 5.26 5.33 5.06 After Humid Aging Rating SE SE SE SE SE SE SE SE Burning Extent. inches 3.1 2.9 3.3 2.8 3.3 2.6 2.2 2.1 Extinguishing Time. seconds 37 36 32 38 30 26 24 Burning Rate. inches/minute 5.02 4.89 5.65 5.23 5.23 5.25 5.01 5.11 Foam Properties Density. lbs./ft.-" 1.56 1.67 1.67 1.58 1.57 1.58 1.63 1.63 1.64 1.65 Air Porosity. 1't./min./ft. 117 53 88 108 88 78 97 94 76 56 Tensile Strength. psi 14.2 17.9 17.9 13.8 12.4 13.1 12.7 13.0 12.8 12.8 Elongation. Percent 158 190 195 156 142 138 142 142 136 137 Tear Resistance, lbs./in. 2.26 2.25 2.82 2.13 2.42 2.14 2.22 2.21 2.21 2.42 4-lnch ILD. lbs/50 in. 25% Diflection 35 39 35 37 4O 41 39 39 40 65% Deflection 64 72 69 68 74 76 73 73 75 76 25% Return 24 25 23 25 26 27 25 25 25 26 Return Value 69 65 66 68 66 66 65 65 64 64 Load Ratio 1.86 1.87 1.94 1.86 1.86 1.86 1.88 1.88 1.88 1.88 90522; (jp npressior set, Percent 4.7 7.8 7.9 4.3 4.4 4.4 4.7 5.1 5.6 5.6

Total weight of polymer is taken as combined weight of polyether polyol. diisocyanate and flame-retardant.

Three ofthe five foam specimens tested were rated SE. a Four of the five foam specimens tested were rated SE.

well as the foams produced in comparative Runs O1 to C-4) were essentially scorch-free. On the other hand, when flexible foams are prepared using the components of Foam Formulation A of Table 1 above and 2,3- dibromopropanol as the flame-retardant in amounts sufficient to provide bromine contents within the range employed in the foam preparations of Tables 11 and 111, the flame-retarded foams exhibit substantial discoloration due to scorching.

What is claimed is:

l. 2.3-dihydroxyprop-l-yl 2,3,7.8-tetrabromooct-1yl ether.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 856 865 Dated December 2 1974 Inventofls) Anthony J. Papa and William R. Proops It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, lines 50-52, that portion of the formula reading 0-CH should read 0-CH2 Column 6, line 62, after "of the polyol" insert a period and delete "In"; line 63, before "producing" insert In lines 63-68, should be' aligned at the margin rather than indented. Column 7, line 17, for "hexadecyldimethy(amine" read hexadecyldimethylamine Column 10, line 11, for "126,000", read 126,600 Column 11, line 47, after "Weight" insert per cent, respectively, of compounds having the Column 12, line 37, for "speciment" read specimen Column 16, line 59, for

lyl" read l-yl Signed and Scaled this twenty-first D ay of October 1975 [SEAL] A ttes t:

RUTH. C. MAfiSGN C. MARSHALL DANN Artesmzg Officer Commissioner ofPatenIs and Trademarks

Claims (1)

1. 2,3-DIHYDROXYPROP-L-YL 2,3,7,8-TETRABROMOOCT-LYL ETHER.